Batch feeding and mixing apparatus



Dec. 20, 1955 F. L.. cARswELL BATCH FEEDING AND MIXING APPARATUS 2sheets-sheet 1 Filed Aug. l2, 1955 1N V EN TOR.

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Dec. 20, 1955 F. L. cARswELL.

BATCH FEEDING AND MIXING APPARATUS 2 Sheets-Sheet 2 Filed Aug. l2, 1953fwd ATTORNEYS.

nited States Patent() BATCH FEEDING AND MIXING APPARATUS Frank LeonCarswell, Kansas City, M0.

Application August 12, 1953, Serial No. 373,313

3 Claims. (Cl. 259-154) This invention relates to an apparatus forfeeding materials, for example, aggregates and a binding medium such asbitumen, Portland cement or the like, to a mixing machine as in themanufacture of concrete or paving product.

The specifications for concrete or paving mixtures usually require thatthe various components be mixed in proportion by weight and the mixingoperation is usually carried out in batches.

it is7 therefore, the principal object of the present invention toprovide an apparatus for feeding the various materials by weight for agiven specified time so as to deliver to the mixing machine, givenquantities of the ingredients in predetermined weight ratios for mixtureof a batch having the specified proportions by weight.

Other objects of the invention are to shut down automatically all of theweighing mechanisms when suiiicient materials are delivered to acollecting hopper preparatory to discharge of the collected materialsinto the mixer, and to provide a time control means for shutting' Fig. 2is an enlarged side elevational view of the feeding mechanism for one ofthe ingredients.

Fig. 3 is a cross section on the line 3 3 of Fig. 2.

Fig. 4 is a fragmentary View of a scale beam, poise` and recorder forindicating weight of the material beingdischarged through a given periodof time.

Fig. 5 is a detail perspective view of the transmission operating a feedbelt and showing the recorder for recording feet of belt delivery duringa given period of time.

Referring more in detail to the drawings:

1 designates a machine adapted for feeding and mixing aggregates with abitumen or similar binding material in a batch and in accordance with aspecied weight ratio of the respective ingredients. The machine includesa base 2 carrying a frame 3 including longitudinal members 4 and 5.Supported by the frame above the longitudinal members 4 and 5 arehoppers 6, 7 and 8 for containing the dry materials such as theaggregates to be used in making, for example, a paving product. Thehoppers have discharge throats 9, and 11 in the bottoms thereof throughwhich the aggregates are discharged into gravimetric feeders 12. Thegravimetric feeders are of the same construction, and the description ofone sutiices for the others. Therefore, only oneof the feeders will bedescribed indetail.

Supported below the feed throat of each of the respective hoppers is adownwardly sloping feed tray 13 ICC suspendedly supported by pairs oflinks 14 and 15 pivoted to the hopper throats as indicated at 16 and tosides of the tray 13 as at 17. The bottom 18 of the tray is spaced fromthe throats a sufficient distance to allow oscillating movement thereoffor promoting discharge of the material as later described.

Formed in each feed throat at the sides thereof adjacent the dischargeend of the feeding tray is an outlet opening 19 which cooperates with alower or forward edge of a corresponding tray to discharge the materialfrom a hopper. Projecting from the sides of the outlet opening 19 arearms 20 supporting a valve member 21 on a shaft 22 that is carried bythe arms 20 and actuated from a remote point through a link 23 havingconnection with a crank arm 24 on the shaft 22. The valve member 21 has`a gate portion 25 movable over the outlet opening 19 to regulate theeffective area thereof so that approximately a desired amount ofmaterial is delivered from the hopper in a continuous stream.

In order to maintain a positive feed of material from the hoppers, eachtray 13 is reciprocated by actuating mechanisms 26. Each actuatingmechanism includes a transmission 27 mounted on cross members 28 of theframe to the rear of the respective discharge throats and which isactuated through a belt connection 29 with a motor 30.

Fixed on the driven shaft of the transmission is a pulley 31 (Fig. 5)for driving a pulley 32 on a transverse shaft 33 (Fig. 2). Thetransverse shaft 33 is located in horizontal alignment with the feedtray on bracket-like supports 34. Slidably mounted in a bearing 3Scarried by each bracket-like support 34 is a tappet 36 having a foot 37eugageable with a cam 38 on the shaft 33. Located in coaxial alignmentwith the tappet in spaced relation therewith is a rod 39 havingconnection with a tray 13. Each tray 13 together with its rod 39 isnormally retained in a forward position by a coil spring 40 sleeved onthe rod and having one end bearing against the bracket 34 and itsopposite end against a collar 41 fixed on the rod 39. Fixed to thefacing end of the rod and tappet 36 are inclined heads 42 and 43 andprojectable between the heads is a control wedge 44 that is supported bya link 45 connected with a scale beam, later to be described.

It is obvious that when the wedge is positioned to ill the space betweenthe heads 42 and 43, full movement of the tappet is imparted to thefeeding tray 13 through the rod 39 to effect maximum movement thereof inone direction for return by the spring 46, but as the wedge is withdrawnto leave space between the wedge and respective heads 42 and 43, thestroke of the feeding tray is reduced proportionate to the spacing sincepart of the movement of the tappet is ineffective until the head and thetappet have moved sufficiently to take up the spaces. Thus by moving thecontrol wedge 44, any predetermined feed of material may be maintainedfrom the throat of the hopper, the primary or rough adjustment beingmade by the valve member 21 and the tine adjustment through the controlwedge 44.

Carried by the longitudinal members 4 and 5 are spaced pairs of scalebeam hangers 47 and 48 forming the fulcrums 49 and 50 for pairs of scalebeams 51 and 52 extending toward each other and having their adjacentends interconnected by links 53 as shown in Fig. 2. One of the scalebeams of the rear pair has an arm 54 that projects rearwardly along thesides of the hopper throat and carries a balancing poise 55 that isslidably mounted thereon to effect balance of the scales. Suspendedlysupported from the respective scale beams in spaced relation with thefulcrum points 49 and 50 are hangers 56 and 56 suspending a feed beltframe 57. lournalled in the frame 57 at the ends thereof are shafts 5Sand 59 and carried thereon are pairs of sprockets 60 and 61 over whichchains 62 and 63 ofa feeder belt 64 operates.-

Fixed to the shaft 60 at one end thereof is a wormgear 65 meshing with aworm 66 which is connected with a driven shaft 67 of the transmission 27through a iiexible joint 68 so that the feed belt is driven at apredetermined speed. By setting the poise 55 on the scale beam, thescale may be made to balance and by moving the poise from the feedbalancing position,- the scale will again effect a balance when theweight' of the materials thereon corresponds with the position of thepoise on the scale beam. Thus as long as the correct amount of materialis carried on the belt, the scale will balance and maintain a continuousstream of material at a constant feeding rate in accordance with theweight thereof.

Should the weight of material on any one of the belts change, the scalefor that belt is thrown out of balance to cause raising or lowering ofthe wedge and increase or decrease of the feeding rate of the tray tocorrect the delivery of the material and maintain the feed in accordancewith the weight of the material. The weight of material may be recordedand any change may be noted by connecting the poise with a recorder 69(Fig. 4). The footage rate of movement of the conveyor may also berecorded by means of an instrument 70 having connection with a drivenelement 71 on the transmission (Fig.

Means is provided for stopping operation of the feeders in case one ofthe hoppers runs out of material, o'r in case the rate of feed shouldchange from that set by the scale beams. Fixed to the frame of themachine adjacent to the balance arm 54 of each feeder is a bracket 72pivotally mounting a mercury switch 73, and fixed to the balance arm 54is a cooperating bracket 74 having inwardly directed fingers 75 and 76(Fig.` 2) to engage the endsv 77 and 78 of a lever 79 carried by themercury switch 73. The fingers 75 and 76 are located relatively aboveand below the e'nds of the lever 79 so that when the beam arm 54 swingsdownwardly because of lack of material on the belt, the finger 75engages the lever to close circuit through the conductors 80 and 81 to asolenoid switch 82. The solenoid switch 82 opens circuit throughconductors 83 and S4 supplying current to the motors 30. The circuitincluding the mercury switches 73 is supplied from a transformer 85 thatis connected with the main line Wires 86 and 87 through branchconductors 88 and 89 (Fig. l). Thus itis obvious that when any one ofthe mercury switches 73 is closed because of lack of or a reduced amountof material, the operation of all the feeders is suspended.

Should. for any reason, one of the feeding mechanisms fail to operate,an excessive amount of material is delivered onto the feeding belt', thescale arm 54 will swing upwardly and the finger 76 onY the beam willtiltl the'mercury switch 73 to effect opening of the motor circuits sothat feed of all of the material will be stopped until the correctlyrelated feeds are again established. A- signal 82 may be connected incircuit with the elect'romagnet 82 to give a visible or audible signalto remote areas that the machine has been shut down.

In operation, the poises 55 of the respective scale mechanisms are seton the scale arms 54 to regulate ac'- tuation of the feeding trays 13 incooperation with the control valves 21 for maintaining a predeterminedfeed of the aggregates from the respective hopper-s according to theweight of the materials being carried in the re-v spective conveyors.

Feed of the materials' is effected by gravity through the effectiveareas of the discharge openings 19 under influence of the vibratingtraysy 13, the' extent of vibration controlling the amount' of feed.Should the amount" of feed onto one of the belts exceed the' specifiedamountby' weight, the increased feed on the belt changes the posi tionof the a'rm S4 for' that unit, which change in position of the beam arm54 effects a corresponding change in the control wedge 44 to slow thefeed tray 13 for that particular mechanism. When the feed is such as toagain maintain the balance as set by the counterpoise 55, the wedge 44for that unit is automatically readjusted to maintain the feed at thedesired amount. Should the poise 55 be moved to change the rate of feed,the action is registered on the recorder 69 (Fig. 4).

The respective aggregates in the proper proportions by weight aredischarged off the ends of the feed belts 62 onto a collecting belt 90.The belt 90 has a run 91 extending under the belts 62 and supported bysprockets 92. The belt is driven continuously through a motor 93 and aspeed-reducing unit 94. The motor 93 is supplied with current throughconductors 95 and 96 when a switch 97 is closed. The belt 90 depositsthe materials in a hopper 98 which is carried above a mixer or pug-mill99.

After the amount of materials have been delivered into the collectinghopper 98 for a given batch, means is provided for shuttingL down thefeed by opening circuit to all of the motors 30. This is effected by atime switch 100 that is contained in the circuit conductors or wires 83and 84. Therefore, when the running time for which the time switch 100has been set is reached, the motor circuits are automatically opened tostop further feed from all of the hoppers. However, the conveyor 90operates continuously to clear the materials therefrom. The hopper 98has an outlet 101 in the bottom thereof that is normally closed by agate 102. The gate may be opened and closed by a motor 103 supplied withcur rent through conductors 104 and 105 that are connected with the mainline conductors 86 and 87. The hopper 98 is large enough to contain anentire batch of materials therein while a previous batch is being mixedin the mixer 99. The motor 103 is operated by switch 106.

When the materials are being discharged into the hopper of the pug-mill,a binding material, such as bitumen in the case of asphalt or water inthe case of concrete, is discharged onto the material through a nozzle107 under pressure of a pump 108. The pump 108 is operated through abelt 109 that is driven by a motor 110. The motor 110 is connected incircuit with the current supply through branch conductors 111 and 112.Since the capacity of the pump is a known factor, a quantity may bedelivered with the' materials into the pug-mill by controlling the timeof pump operation. This is accomplished by a time switch 113 which isconnected in the circuit wires 111 and 112 so that it may be set to stopthe pump motor when the required amount of fluid has been delivered tothe pug-mill; After the materials are delivered to the pug-mill, theyare thoroughly mixed therein by means of mixing devices 114 which areoperated through a belt 115 drivenby a motor 116. The motor 116 issupplied with current' through branch conductors 117 and 118. The mixingtime for' the materials is controlled by a time switch 119.

After the batch has been mixed, it is discharged from the pug-millthrough an outlet into trucks or other conveyances used in moving theproduct to the place of use.

Switches 121, 122 and 123 are provided in conductors 83, 112 and 118 formanual operation in place of the time switches 100, 113 and 119 whenweighing, collecting and mixing ingredients'used in the apparatus.

From the foregoing, it is obvious that I have provided a simpleapparatus for mixing a product in batch and which assures that the batchcontains the various ingredients in accordance with the weight thereofso as to conform with standard specifications.

What I claim and desire to secure by Letters Patent is:

l. machinev for mixing aggregate materials in batch including aplurality of weight-controlled feeding and conveying" mechanisms foreach material and having dischargeends, actuators for each of saidfeeding mechanisms including a motor, a common current supply circuitconnected with said motors, a time switch in said circuit 'for .stoppingoperation of the weight-controlled feeding means after a predeterminedtime interval, a collecting hopper, a conveyor extending under thedischarge end of each Weight controlled feeding means and havingdischarge into the collecting hopper for receiving the weighed materialdischarged from each weight controlled feeding means for conveying thematerials to the collecting hopper, a mixer for receiving the materialsfrom the collecting hopper, a nozzle for discharging a liquid on thematerials delivered to the mixer, a pump connected with the nozzle forsupplying the liquid, a motor connected with the pump, a circuitconnected with the motor for supplying an electric current, and a timeswitch in the last-named circuit for stopping operation of the pumpafter a predetermined time interval.

2. A machine of the character described including a plurality of hoppershaving outlets for separate aggregate materials contained in saidhoppers, valves controlling the outlets to maintain a predetermineddischarge of materials from the outlets, weighing means below each ofsaid outlets for weighing and discharging the weighed material, aconveyor extending along the discharge of said weighing means forreceiving discharge from all of the weighing means and having adischarge end, a collecting hopper at the discharge end of the conveyorfor receiving the material from the conveyor, means actuated by saidweighing means for regulating discharge of material from said outlets,timing means for suspending feed by said weighing means after apredetermined time interval, and means for continuing operation of theconveyor after the timing means has stopped the Weighing means to assurecollection of all the materials into the collecting hopper.

3. A machine of the character described including, a plurality ofstorage hoppers having outlets for materials contained in said hoppers,a separate feeding means below each outlet to maintain a predetermineddischarge of materials from the outlets, a collection conveyor common toall the feeding means of the storage hoppers, a collection hopper,conveying means in receiving position relatively to all of said feedingmeans and having discharge into the collection hopper for dischargingthe materials into the collection hopper, scale means for weighing thematerial carried by the conveying means, means actuated by said scalemeans and connected with said feeding means for regulating discharge ofmaterial from said outlets onto the conveying means, means for actuatingthe conveying means, a circuit supplying current to the actuating means,and a time switch in said circuit for stopping operation of theactuating means after a predetermined time period,

References Cited in the le of this patent UNITED STATES PATENTS1,764,583 Stern June 17, 1930 2,256,422 Brayer Sept. 16, 1941 2,263,797Christensen Nov. 25, 1941 2,285,765 Carswell June 9, 1942

